Means for transferring fluids in an absorption refrigeration system



Y 1962 E. P. WHlTLOW ETAL 3,046,756

MEANS FOR TRANSFERRING FLUIDS IN AN ABSORPTION REFRIGERATION SYSTEMFiled May 5, 1960 1955 GREEK E'VHPOEHTOE IN V EN TORS'; 153 m FZVMW/United States atet 3,046,756 Patented July 31, 1962 free 3,046,756 MEANSTRANSFERR'WG FLUIDS m AN AESfiRPTiGN REFREGERATIDN SYSTEM Eugene P.Whitlow and Robert W. Fink, Benton Harbor,

Mich, assignors to Whirlpool Corporation, a corporation of DelawareFiled May 3, 194%, Ser. No. 26,693

3 Claims. (Cl. 62-14l) a This invention relates to absorptionrefrigeration systems and in particular to means for transferring fluidsfrom the low pressure portion to the high pressure portion of a twopressure absorption refrigeration system.

In the conventional two pressure absorption refrigeration system,circulation of the refrigerant fluid throughout the system is caused bythe pressure differentials between different portions thereof. At onepoint in such a system, conventionally at the generator, energy isintroduced to the system in the form of heat providing a high pressurerefrigerant vapor conventionally delivered to a condenser wherein thevapor is condensed to a liquid at this high pressure. The liquifiedrefrigerant is then delivered to an evaporator wherein it evaporates,drawing the heat of vaporization from the associated refrigeratorelements and thereby effecting the desired refrigeration. The lowpressure vaporized refrigerant is delivered from the evaporator to anabsorber wherein it is reliquified, as

by absorption in a liquid, and is delivered from the absorber to thegenerator, completing the cycle.

The present invention is concerned with a new and improved means for usein such a refrigeration system for pumping the low pressure liquifiedrefrigerant and absorbent from the absorber to the generator against thehigh pressure of the vaporized refrigerant therein.

A principal feature of the invention is, therefore, the provision of anew and improved means for pumping refrigerant in a refrigerationapparatus.

Another feature is the provision of such a pumping means in anabsorption refrigeration system having a first portion containing highpressure fluid and a second portion containing low pressure fluid, thepumping means including a pump connected between the first and secondportions of the system for pumping fluid from the low pressure portionto the high pressure portion, and means using a portion of the energy ofthe high pressure fluid for operating the pump.

A further feature of the invention is the provision of such a pump meanswhich is of simple and economical construction providing extendedmaintenance-free service.

Still another feature is the provision of such a pump means which may bereadily controlled for adjustment of the rate of pumping.

A still further feature is the provision of such a pump means arrangedfor continuous functioning notwithstanding changes in the fluid pressureconditions within the system.

Another feature is the provision of a pumping mechanism which alsoserves as the expansion valve and pressure reducing valve in the system.

A yet further feature of the invention is the provision of such pumpmeans which utilizes effectively minimum power, and which issubstantially silent in operation.

Other features and advantages of the invention will be apparent from thefollowing description taken in connection with the accompanying drawingwherein:

FIGURE 1 is a schematic view of a refrigeration system including a pumpmeans embodying the invention, the pump means being shown as near theend of the portion of the cycle of operation thereof wherein refrigerantfluid is delivered to the generator.

FIGURE 2 is a view similar to that of FIGURE 1 but with the pump meansshown as near the end of the retraction portion of the cycle ofoperation thereof;

" erant is used for operating the pump means.

' space 22a.

In the exemplary embodiment of the invention as disclosed in thedrawing, an absorption refrigeration system generally designated ltlincludes a generator 11, a condenser 12, an evaporator 13, and anabsorber 14 all of conventional construction. Illustratively, therefrigerant may comprise ammonia and the liquid absorbent for liquifyingthe refrigerant in the absorber may comprise water. The presentinvention is concerned with a new and improved pump means generallydesignated for pumping the water which is rich in ammonia refrigerant,hereinafter referred to as rich liquid, from absorber 14 to generator ll wherein the rich liquid is heated to vaporize the ammonia refrigerantfor delivery to condenser 12. The water which is weak in ammoniarefrigerant as a result of the boiling of the ammonia vapor therefrom,and which is hereinafter referred to as weak liquid, is returned fromthe generator through the pump means 15 wherein a portion of thepressure energy of the water is utilized for operating the pump means.Similarly, refrigerant condensed in condenser 12 is delivered toevaporator 13 through a portion of the pump means 15 wherein a portionof the pressure energy of the condensed refrig- Control of the cyclingof the pump means is obtained by means of a three-way valve 16 which maybe operated by a suitable conventional tirner 17 for continued cyclingof the pump means 15 at preselected rates of delivery thereof.

More specifically, pump means 55 includes a pump 18, a first pilot valve1?, and a second pilot valve 26. The outer housing of pump 18 is definedby a first cylindrical portion 21 defining a first space 21a and asecond, diametrically larger cylindrical portion 22 defining a second Astepped piston 23 includes a first portion 24 slidable in housingportion 21 and an increased diameter portion 25 slidable in housingportion 21. The large diameter housing portion 22 is closed by an endwall 26 having an axial opening 27 through which extends a rod 28secured at its inner end to piston portion 25 and its outer end to apower piston 29* slidably reciprocable in a small diameter cylindricalextension 30 of housing portion 22 defining a space 39a. As shown,piston portion 24 is slidably sealed to housing portion 21 by a pistonring 31, piston portion 25 is slidably sealed to housing portion 22 by apiston ring 32, power piston 29 is slidably sealed to housing extension30 by a piston ring 33, and rod 28 is slidably sealed to housing endwall 26 by a shaft seal 34.

Piston 23 is biased away from end wall 26 (to the left as seen inFIGURE. 1) by a coil spring bottomed in an annular groove 36 arrangedcoaxially in piston portion 25 and opening toward end wall 26, the outerend of the spring bearing against the end wall concentrically of rod 28.Radially inwardly of groove 36, piston portion 25 is extendedlongitudinally outwardly to define a cylindrical boss 37 which engageshousing end wall 26 to preclude complete surface contact of the pistonwith the end wall.

Pilot valve 19 includes a stepped cylindrical housing 38 slidablyreceiving a relatively large diameter piston 39 in a large diameterportion 46 defining a first space 40a thereof and a relatively smalldiameter piston 41 in a small diameter portion 42 defining a space 42::thereof,

' the pistons being connected by a rod 43 for conjoint coaxialreciprocable movement in housing 38. As shown,

acaeves space 48a therein, a relatively small diameter piston 49slidably received in a small diameter portion 55 of the housing defininga second space 56a therein, a rod 51 connecting the pistons, a pistonring 52 slidably sealing the piston 47 to the housing portion 48 and apiston ring 53 slidably sealing the piston 49 to the housing portion 55Rich liquid is delivered from absorber 14 into space 22a of pump 18between piston 25 and end wall 26 by means of a conduit 54 provided witha check valve 55 precluding reverse flow therethrough. The rich liquidis d livered from pump 18 to generator 11 by means of a conduit 56 aconduit 61 to housing extension space 311a adjacent end wall 26.Connected to conduit 61 adjacent valve 16 is another conduit "62 havingone branch 63 connected to one end of the housing portion 48 of pilotvalve 25?, and a second branch 64 connected to the corresponding end ofhousing portion 46 of pilot valve 19.

pressure refrigerant vapor is delivered from generator 11 to condenser12 through a conduit 65. The condensed refrigerant is delivered fromcondenser 12 to space 50a of pilot valve 20 between pistons 47 and 49thereof by a conduit 66. A conduit 67 connects space 50a at a point tothe right of piston 49 when it is positioned at the leftward extreme ofits movement, as shown in FIGURE 1, to the end of hous ng portion 20 ofvalve 18 for delivery of the high pressure refrigerant liquid to space20a. Evaporator 13 is connected to the space 50a of pilot valve 20 by aconduit 68 and space 42:: of pilot valve 19 is similarly connected toabsorber 14 by a conduit 69. Conduit '69 is connected to three-way valve16 by a conduit 70 and a conduit 71 connects conduit 7 to the outer endof housing extension 30. A conduit 72, connects the end of housingportion 21 opposite end wall 26 of pump 18 to space 42a of pilot valve19 at a point spaced from he right-hand end of the housing portion 42 tobe slightly 0 the left of the piston 41 when the piston is at theextreme right position as shown in FIGURE 1.

The pumping of the low pressure rich liquid from ab sorber 14 togenerator 11 is eifected by a movement of piston 23 to the right fromthe position .of FIGURE 2 to the position of FIGURE 1. This cycle of theoperation of the refrigeration system is initiated by rotating movablevalve member 60 of three-way valve 16 from the position of FIGURE 2 tothe position of FIGURE 1, which movement may be automatically efiectedby timer 17. This rearrangement of valve 16 causes pilot valves 19 and20 to move substantially immediately from the position of FIGURE 2 tothe position of FIGURE 1, and the piston 23 to move slowly from theposition of FIGURE 2 to the position of FIGURE 1. More specifically,high pressure weak liquid is directed by valve 16 from conduit 59through conduit 61 into housing extension space 30a to urge piston 29 tothe right as seen in FIGURE 1, from conduit 61 through conduits 62 and63 into space 48a of pilot valve 20 to urge pistons 47 and 49 to theleft, and through conduit 64 to space 49a of pilot valve 19 to urgepistons 39 and 41 thereof to the right. When the pistons of the pilotvalves 19 and 20 reach the positions of FIG- URE 1, high pressure weakfluid passes from conduit 58 through space 42a of pilot valve 19, andthrough conduit 72 into space 21:: of pump 18 from the left side ofpiston portion therein, and concurrently high pressure condensedrefrigerant passes from the condenser through conduit 66, the space 50aof pilot valve 20, and through conduit 67 into the left end of space-20aof pump 18 from the left of piston portion 24. The right-hand end ofhousing extension space 3% is connected to the low pressure absorber 14by conduits 71, 70 and 69. Thus, while the piston 23 is effectivelybalanced by the fluid pressures on opposite sides thereof, the piston 29is forced to the right by the pressure differential between the pressureweak liquid in housing extension space 31):: to the left of piston 29and the low pressure liquid to the right thereof. Thus, piston :23 ismoved to the right against the bias of spring 35 forcing the rich liquidfrom the right-hand end of chamber 22, through conduit 56 and intogenerator 11, check valve 55 precluding back flow of the rich liquid toabsorber 14. This rightward movement of piston 23 con tinues until thepiston portion 37 abuts end Wall 26 whereby a predetermined volume ofrich liquid is delivered from pump 18 to generator 11.

Refrigeration system 10 remains in the arrangement" I 19 and 29 aresubstantially immediately transferred from the position of FIGURE 1 tothe position of FIGURE 2 and piston 23 is slowly forced to th eleftmostposition of FIGURE 2. More specifically, high pressure condensedrefrigerant delivered from conderiser 12 through "conduit 66 to withinhousing 46 of pilot valve 20 between pistons 49 and 47 thereof movesthepistons to the right against the low pressure actingo'n the right sideof piston 47 as a result of connecting the right-hand end of space 48athrough conduits 63, 62 and 61, valve 16, and conduits 70 and 69 toabsorber 14. Similarly, high pressure liquid delivered from generator 11 through conduit 58 to housing 38 of pilot valve 15 between pistons 41and 39 thereof urges the pistons to the left against the low pressure inconduits 64 and 6 2 to conduit 61. As both sides of piston 29 aresubjected to the same low pressure as a result of the connection ofconduits 71 and 61 jointly through conduits and 69 to absorber 14,piston 29' is inefiectual in positioning the main piston 23, permittingcoil spring 35 to urge the piston 23 slowly to the left whereupon richliquid flows from absorber 14 through conduit 54 and into space 22abetween piston 23 and housing "end wall 26. Concurrently, the leftwardmovement of piston 23 causes piston portion 25 to force the Weak liquidin space 21a to the left of piston portion 25 outwardly therefromthrough conduit 72, through space 42;: of pilot valve 15,

- and through conduit 69 to absorber 14, and causes piston portion 24 toforce condensed refrigerant 'in space 21a of pump 15 therefrom throughconduit 67, space Slla of pilot valve 20, and conduit 68 to evaporator13.

It should be noted that in moving to the left, piston 23 forces apredetermined volume of condensed refrigerant, previously delivered fromcondenser 12 to pump 18, from the pump to evaporator 13, andconcurrently forces a predetermined volume of weak liquid, previouslydelivered to pump 18 from generator 11, to absorber 14, the volume ofweak liquid delivered to the absorber plus the volume of refrigerantdelivered to the evaporator at this time being slightly greater than thevolume of rich liquid previously delivered from the absorber to thegenerator as a result of the rightward movement of the pump piston.Thus, a simple and accurate adjustment of the pumping rate may beefiected by controlling the rate at which the valve 16 is cycled.I-llustratively, in a refrigeration system providing one ton ofrefrigeration, the pump may be arranged to deliver approximatelyone-quarter gallon per minute with a pressure difierential between thepressure and low pressure portions of the system of approximately 250pounds per square inch and with the pump being cycled approximately tentimes per minute.

The refrigeration apparatus 10 has extended maintenance-free life as aresult of the effectively minimized wear of the sealing piston rings.More specifically, piston rings 31 and 32 have substantially equalpressures on each side thereof at all times. Piston ring 33 has equalpressures on opposite sides thereof during the entirehalf cycle whenvalve member 60 is arranged in the position of FIGURE 2 and shaft sealring 34 has equal pressures on opposite sides thereof at all times otherthan when the pilot valves 19 and 20 are being repositioned.

Because of the positive pumping operation of refrigeration system 10,operation of the system is continued notwithstanding a reduction in theamount of liquid in the system resulting from a reduction in the amountof heat delivered to the generator, a change in the ambient conditionsrelative to any or all of the generator, condenser, evaporator, andabsorber, or gradual changes within the system. Under these conditions,the operation of pump 18 is effected by the high pressure vapor in lieuof the high pressure condensed refrigerant.

Having described our invention as related to the embodiment shown in theaccompanying drawing, it is our intention that the invention be notlimited by any of the of condensed refrigerant from said condenser to asecond portion of said chamber at said opposite side of the displacementmember during said one movement thereof and delivering said volume ofcondensed refrigerant to said evaporator during said opposite movementof the displacement member; reciprocative power means for reciprocatingthe first displacement member including a second displacement membercoupled to said first displacement details of description, unlessotherwise specified, but rather be construed broadly within its spiritand scope as set out in the accompanying claims.

The embodiment of the invention in which an exclusive property orprivilege is claimed is defined as follows:

1. In an absorption refrigeration system having a first portioncontaining high pressure fluid and a second portion containing lowpressure fluid, apparatus comprising: a pump for pumping fluid from thesecond portion to the first portion including a housing having an inletand an outlet at one end, a port at the other end, and a piston in thehousing reciprocable toward and from said one end; first passage meansfor delivering fluid from said second portion of the system to saidinlet upon spacing of said piston from said one end; a second passagemeans for delivering fluid from said outlet to said first portion of thesystem upon juxtaposing of said piston to said one end; a third passagemeans including a control valve responsive to pressure difierentialsthereacross for selectively connecting said port with either of saidfirst and second portions of the system; means for selectively applyingpressure difierentials to said control valve for cyclically operatingthe control valve at preselected time intervals; and piston means at oneend of said pump and arranged to use a portion of the energy of the highpressure fluid directed thereto by the control valve for reciprocatingthe piston.

2. In an absorption refrigeration system having a first portionincluding a generator containing high pressure Weak liquid and acondenser containing high pressure condensed refrigerant, and a secondportion including an absorber containing low pressure strong liquid andan evaporator, apparatus comprising: a pump having means defining -achamber and a first displacement member reciprooable in said chamber;first flow passage means communicating with said chamber at one side ofthe displacement member and with said absorber and said generator fordelivering a predetermined volume of rich liquid from said absorber tosaid chamber during one movement of the displacement member anddelivering said volume of rich liquid from said chamber to saidgenerator during an opposite movement of the displacement member; asecond flow passage means between said generator and said absorber andincluding a first pilot valve selectively delivering a predeterminedvolume of high pressure weak liquid to a first portion of said chamberat the opposite side of the displacement member during said one movementthereof and delivering said volume of weak liquid to said absorberduring said opposite movement of the displacement member; a third flowpassage means between said condenser and said evaporator and including asecond pilot valve selectively delivering a predetermined volume member;means biasing the displacement members in one direction; and valve meanscyclically connecting said power means alternately to said high pressureand low pressure portions of the refrigeration system at preselectedintervals.

3. In an absorption refin'geration system having a first portionincluding a generator containing high pressure weak liquid and acondenser containing high pressure condensed refrigerant, and a secondportion including an absorber containing low pressure strong liquid andan evaporator, apparatus comprising: a pump having means defining achamber and a first displacement member re ciprocable in said chamber;first flow passage means communicating with said chamber at one side ofthe displacement member and with said absorber and said generator fordelivering a predetermined volume of rich liquid from said absorber tosaid chamber during one movement of the displacement member anddelivering said volume of rich liquid from said chamber to saidgenerator during an opposite movement or" the displacement member; asecond flow passage means between said generator and said absorber andincluding a first pilot valve selectively delivering a predeterminedvolume of high pressure weak liquid to a first portion of said chamberat the opposite side of the displacement member during said one movementthereof and delivering said volume of weak liquid to said absorberduring said opposite movement of the displacement member; a third flowpassage means between said condenser and said evaporator and including asecond pilot valve selectively delivering a predetermined volume ofcondensed refrigerant from said condenser to a second portion of saidchamber at said opposite side of the displacement member during said onemovement thereof and delivering said volume of condensed refrigerant tosaid evaporator during said opposite movement of the displacementmember; power reciprooative means for reciprocating the firstdisplacement member including means defining a second chamber and asecond displacement member coupled to said first displacement member andreciprocable in said second chamber; fourth flow passage means betweenthe generator and absorber and connecting said second chamber at oneside of said second displacement member to said absorber, and includinga cycling control valve connecting said second chamber at the oppositeside of said second displacement member at preselected intervals to saidabsorber and said generator; means biasing the second displacementmember in a direction opposite to that in which it is urged when saidsecond chamber at said opposite side of the second displacement memberis connected to said generator.

References Cited in the file of this patent UNITED STATES PATENTS1,527,833 Buchel Feb. 24, 1925 1,866,825 Smith July 12, 1932 2,929,222Lang Mar. 22, 1960 FOREIGN PATENTS 840,249 Germany May 29, 1952

